Embodiments of the system relate generally to an integrated voltage/volt-ampere reactive (volt/var) control system and more specifically to a system and method for controlling a voltage profile in a power system.
The basic structure of an electric power system typically comprises various hardware elements such as generators, transformers, and real-time monitoring equipment, and software such as power flow analysis software, fault detection software, and restoration software for generation, transmission, and distribution of electricity.
With increased distributed generation, the integration of distributed generators into existing power systems presents technical challenges such as voltage regulation and increased duty cycle of operation of grid assets such as transformer taps and capacitor banks switches. Power quality is an essential customer-focused measure and is greatly affected by the operation of a distribution and transmission network.
Large inductive loads such as air conditioners, furnaces, dryers, and the like can consume reactive power (VARs) in addition to real power (Watts). Transferring reactive power over transmission lines and distribution feeders involves transferring additional current which results in power (I2R) losses that have to be supplied by utilities. Since residential power meters typically only measure Watts that are used to determine customer billing requirements, utilities want to minimize the number of VARs consumed. This result is generally achieved by switching in capacitor banks to compensate for VAR losses locally in distribution systems.
In addition, power system operators ensure the quality of the power supplied to the customers by maintaining the load bus voltages within their permissible limits. Any changes to the system configuration or in power demands can result in higher or lower voltages in the system. With the increased penetration of Distributed Generation, such as Solar PV, the voltage excursions and associated variability increases on the local distribution networks. This results in excessive operation of transformer taps and capacitor bank switches, thereby reducing their operating life. Further, these are electro-mechanical equipment, which are not able to effectively chase the fast variability of distributed energy resources. On the other hand, distributed energy resources can act quickly to regulate their reactive power output and respond to the fast voltage variations.
For these and other reasons, there is a need for an improved integrated volt-var control system.